The present invention relates to communication system networks, particularly, to method and apparatus for controlling quality of communication services in a communication network.
In network communication systems, a source user may communicate to a terminal user via a network that includes a number of network elements. Such network elements are normally network traffic router elements and network edge elements. The communication between the users takes place by creating a communication flow among the network elements. The communication flow is then used to transmit data packets. The creation of the communication flow and transmission of the data packets may occur at the same time in some system. Such systems may include Asynchronous Transfer Mode (ATM), Switched Virtual Circuit, and Internet Protocol based network technologies.
A communication network may provide communication traffic flow control based on state information collected and analyzed by each network element in a communication flow. Each network element independently may control the communication traffic based on a pre-defined communication flow profile. Each network element processes the traffic flow that passes through it to control the traffic flow. A commonly known method called Differentiated Services Architecture (DiffServ) is used to control communication traffic flow. A copy of the standard outlining such architecture may be obtained by contacting IETF Secretariat, c/o Corporation for National Initiatives, 1895 Preston White Drive, Suite 100, Reston, Va. 20191-5434, USA; or a copy may be obtained by accessing an internet wed site located at WWW.ietf.Com.
Referring to FIG. 1, a conceptual block diagram of a communication network 100 is shown. The quality of service in such a network is managed by encoding a value in a DS field of data packets originated at an edge network element 110. The internal network elements 120 and 130, when the packet is passing through, assign different Per-Hop behavior to each traffic flow. Such behavior is according to a predefined traffic flow arrangement in the network element. A specific traffic flow profile is selected for each packet depending on the value in the DS filed of the data packet. The value of DS field normally is assigned by an edge network element through, possibly, a negotiation with a source user.
The source users 150 connect to edge network elements 110 for receiving communication services. Such source users may require different services such as voice, data and video services. The terminal users 160 may be the end users of a number of communication traffic flows created for providing the communication services. At the terminal users, there may be other edge network elements such as edge network elements 140. A xe2x80x9cUxe2x80x9d interface 170 may be a flexible wire-less or wire-line connection interface between the end users and the network elements. A xe2x80x9cDSxe2x80x9d interface 180 between other network elements is based on a predefined standard such as DiffServ standard. Each network element, such as network elements 120 and 130, passes each data packets in the communication flow according to a communication traffic profile selected based on a DiffServ value assigned in the DS field of the data packet.
Referring to FIG. 2, a block diagram of a network element 210 is shown. A packet classifier 220 selects data packets in the data stream based on the content of some portion of the data packet header such as the DS field. Classifier 220 is used to steer packets of data based on a communication traffic flow profile. Each data packet with a specific marked DS field may pass according to predefined communication traffic flow latency set by the profile. Conditioning communication traffic flow may occur at classifier 220. A traffic meter 230 measures the temporal property of the traffic flow passing through the classifier 220. The meter 230 passes state information to other traffic conditioning functions to trigger a particular action for each packet depending on whether the packet is in or out of a predefined profile. A marker 240 marks a packet of data to a particular DS value such that the packet passes through according to a specific profile. The shaper and dropper 250 delay or discard the data packet to condition the traffic flow according to a predefined traffic profile. Such traffic flow is simple and does not take into account the activities and communication traffic flows at other network elements in the system.
Therefore, there is a need for an effective traffic flow management control that takes into consideration an aggregate traffic flow across the network.